Process of concentrating ores and minerals by flotation



Patented July .28, 1931 UNITED STATES PATENT OFFICE WILLIAM .A. DOUGLAS S, OF PENNS GROVE,

DE NEMOURS & COMPANY, OF WILMI .DELAWABE NEW JERSEY, ASSIGNOR TO E. I. DU PON'I NGTON, DELAWARE, A. CORPORATION OF No Drawing.

This invention relates to the concentration of certain ores and minerals by flotation and comprises more particularly the concentration of such ores and minerals by means of a new class of organic flotation reagents.

This application is in the nature of a continuation in part of an application filed by the same inventor February 25, 1925, Serial 'No.11,589.

It has been shown by Sayre in U. S. P. #1,512,189 that the heavy'metal salts of Xanthic acid are admirable flotation agents in a non-acid or alkaline pulp. Such xan thates are claimed to have a marked selective action on sulfide minerals, as distinguished from gangue minerals and cause the sulfide minerals to float readily with an attendant high recovery of metal values. Both the heavy metal and alkali metal salts of xanthic acid While of unquestioned value as flotation agents are open to certain objections in re spect to urity and stability.

One 0 ject of my invention is to provide a class of V flotation agents which not only possess the good flotation properties resulting from the presence of the chemically reactive xanthic acid group, but which are chemically stable, and have flotation properties equal to or better than those possessed by the heavy metal salts of xanthic acid.

Moreover, I have found it possible to produce compounds of this type in a very pure state.

I have discovered that the compounds ob- 5 tainablo by treating a metal salt of xanthic acid or of an analogous sulfur or-O containing acid with cyanogen halide as distinguished from metal xanthates, constituteexcellent flotation agents-and possess the desirable properties specified above.

These new organic flotation agents have in general a molecular structure indicated by the formula II II where R represents an alkyi group, hath radi cals Y represent'the same eieraent of the group consisting of O and S, both 5 Y" represent the same element of the Application filed July 9, 1928. Serial No. 291,494.

consisting of O and S, and Y either 0 or S.

The aliphatic derivatives of xanthic acid constitute a class of this broad group of compounds which has been found to contain compounds particularly Well adapted for use in flotation and my invention will be described hereinafter with more particular reference thereto, as the preferred embodiment.

The flptation agents of this class of compounds have the general line formula:

Where and R represent the same or diflerent hydrocarbon radicals, preferably alkyl radicals. This class includes the correspondng symmetrical Xanthyl monosulfid'es (that 1s, Xanthic acid anhydrides such as di-ethylxanthyl monosulfide, G l-I CS.S.CS.OC H As examples of other xanthic derivatives adapted for use as flotation agents there may be mentioned:

Di-methyl-xanthic anhydride, Di-propyhxanthic anhydride, Di-butyl-Xanthic anhydride, Di-aniyl-xanthic anhydride, Ethyl-butyl-Xanthic anhydride, Methyl-ethyl-xanthic anhydride, Methyl-butyl-Xanthic anhydride. I Flotation tests with ethyI-xanthic anhydricie, carried out on Inspiration ore gave the following results in comparison with potassium xanthate.

represents Potas Ethyl slum xanthic .xananhythate drldc Lbs. reagent/ton ore 0. 004 0. 005 Per cent copper in heads 1.03 1. 0.! Per cent copgv in rougher tailingis 0. 41 0. 32 Per cent eopri recovered in concentrate- 62 2 70. 4 Per cent zipper in rougher concentrate 12. 14. 90

The symmetrical anhydrides, in generai, may he prepared by eating the appropriate metal aanthate or suit of an analogous acid with a cyanogen halide as iliustrated by the ea uation;

The unsymmetricai isionosuifiies may be crystallization from absolute alcohol.

similarly prepared by treating a mixture of the appropriate alkyl xanthates with cyanogen halide.

The xanthic anhydrides may also be pre pared as a by-product by the action of the corresponding alkyl chlor formate and potassium alkyl xanthate. Ethyl xanthic anhydride, for example, may be prepared by the action of ethyl chlor formate on potassium ethyl xanthate. This crude produce may be urified by separating the xanthic anhydride may be urther purified, if desired, by repurified product so obtained contained 45.6% sulfur. Welde (J. fur. Prak. Chem1e (2) 15,

31877), p. 45) assumes that xanthic anhy-,

ride is formed by this method according to the following equation:

30.11.0- SK+2C1.(OC:H 2KC1:+

The various crude products prepared by the methods indicated above may contain in addition to the major products other xanthlc compounds. Suchproducts, however, may

be employed in their crude state and may be introduced into the 'pulpor ore at any time prior to the flotation operatiom While the xanthate-compounds have been employed above for the purposes of illustra- 'tion, it will be understood from What has been said above by those skilledin the art that sulfur atoms may be replaced by oxy en or vice versa either in the double bon ed positions or the single bonded positions. It is obvious that a large number of permutations and combinations is possible. The resulting compounds may be of any of thetypes indicated in the table below. 7

ferent alkyl-radicals.

Although the new flotation agents have been found to be effective to a certain extent in an acid 111p, much better results are generally obtained by operating with a non-acid pulp, that is, one which has been rendered neutral or alkaline, referably with lime. A frothin agent, as or example, terpineol, is also, or inarily necessary since the new flotation agents have little, if any, frothing power.

I claim:

1. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a coolin to 5 C. The resulting product froth flotation operation in the presence of the product resulting from the reaction between a compound of the group consistin of metal xanthates and analogues thereo and a cyanogen halide.

2. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a compound having the general formula:

II II where R and R represent alkyl groups, both radicals Y represent the same element of the group consisting of O and S, both radicals Y represent the same element of the group consisting of O and 'S and Y' represents an element of the group consisting of O and 3. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a compound having the general formula:

II II where R and R represent alkyl groups, both radicals Y represent the same element 0 the group consisting of O and S, both radicals Y represent the same element of the group consisting of O and S and Y represents an element of the group consisting of O and S but Y, Y" and Y do not all represent the same element of the group consisting of O and S.

4. In the process of concentrating ores-by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a compound having the general formula;

where R and R represent alkyl; groups, Y represents 0, Y represents S and Y' represents an element of the group consisting of O and S.

6. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of a compound having the formula:

prises subjecting the mineral in the form of a pulp to a froth flotation operation in the presence of an alkyl xanthic anhydride.

10. The improvement in the concentration of minerals by froth flotation which comprises subjecting the mineral in'the form of a pulp to a froth flotation operation in the presence of an ethyl xanthieanhydride.

11. In the process of concentrating ores by flotation, ing the ore in the form of a pulp to a froth flotation operation in the presence of the product resulting from the reaction between minerals by froth flotation which com the step which comprises subject-o a pulp to a froth flotation operation in the presence, of dibutyl-xanthic anhydride.

18. The improvement in the concentration of minerals by froth flotation which comprises subjecting the mineral .in the form of a pulp to a froth flotation o eration in the presence of a xanthic anhy ride from the roup consisting of dimethyl-xanthic anhyflride, dipropyl-xanthic anh dride, dibutylxanthic anhydride, diamy -xanthic anhydride,ethyl-butyl-xanthic anhydride, methylethyl-xanthic anhydride and methyl-butylxanthic anhydride. a In testimony whereof, I aflix my signature.

WILLIAM A DOUGLASS.

' an alkali metal xanthate and a cyanogen halide. 1

12. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence'of the product resulting from the reaction between an alkali metal xanthate andcyanogen chloride.- I

13. In the process of concentrating ores by flotation, the step which comprises sub'ecting the ore in the form of a pulp to a frat flotation operation in the presence of the product resulting from the reaction between sodium ethyl xanthate and a cyanogen halide.

14. In the process of concentrating ores by flotation, the step which comprises subjecting the ore in the form of a pulp to a froth flotation operation in the presence of the product resulting from the reaction between sodium ethyl-xanthate and cyanogen chloride.

15. The improvement in the concentration of minerals by froth flotation which comprises subjecting the mineral in the form 01 a pulp to a froth flotation operation in the presence of diethyl-xanthic anhydride.

16. The improvement in the concentration of minerals by froth flotation which comprises subjecting the mineral in the form of a pulp toa froth flotation operation in the presence of dimethyl-xanthic anhydride.

17. The im rovement in the concentration of minerals y froth flotation which comprises subjecting the mineral in the form of 

